haemodialysis Flashcards
how does haemodialysis work
in haemodialysis, blood from the patient is removed and pumped into a dialyser, where toxins like urea, and excess salts + water can be removed from the blood via diffusion and then returned to the patient
why does an av fistula have to be created
it is created by surgically joining an artery with a vein. arteries have a high blood pressure but are located deep within the arm and are difficult to reach. the av fistula ensures blood pressure in the vein is high while still being accessible
how is the dialysis tubing built to ensure highest rate of diffusion
the dialysis tubing is partially permeable, allowing small molecules to pass through. the tubing is narrow, long and coiled to increase the surface area to volume ratio, speeding up rate of diffusion of substances. the direction of blood flow is opposite to the flow of the dialysate, as counter current solution maintains the concentration gradient of diffusion
